Signaling system.



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SIGNALING SYSTEM. APPLICATION FILED IIEc.29. IsIs.

Patented Im, 11,191?

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STANLEY s. AfwariarnserMourir vEnnoiv',`1vEw renie assrencn freWESTERN` ELECTRIC COMPANY, rnconroaa'rnnycr einen, n.

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To @ZZ-whom izmay concern:

Be it `known that L'STANLEY S. A. WAT- nrNs, a subject of the King of Great Britain, residing at Mount Vernon, inthe county of wWestchester and State of New York, have invented certain vnew and useful Improvements in Signaling Systems, of vwhich the following is a full, clear, concise, and eXact description. t, This invention relates to Signaling systems in which `each signaling device isV adapted for actuation by current of `a single polarity, and is more particularly applicable to multi-station telephone lines wherein it is de -sirable to obtain ,selective signaling of the several subscribers stations.

In selective signaling system .of this type, heretofore known,y the margins of operation of the signaling devices have been comparatively low, or if these marginshave been increased by the use of auxiliary apparatus in connection with the .signaling devices, the margins obtainable in the .associated supervisory signaling apparatus have been necessarily sacrificed. These defects have been caused bythe-lack ofcopcration between the signaling devices and the source of signaling current, as will be hereinafter more fully explained. y

One of the objects, therefore, ofthis invention isthe provision of a source of signaling current to coperate with the associated signaling devices in order to give satisfactory margins of operation, and, there-V fore, good selection. Another vobject of this invention is the production of a `signaling system in which the signaling devices may be` of such a nature that not only do they allow goodselection in signaling, but at the same time theydo` not impair the operation.

of the associated .supervisory signalin apparatus. Still another object `is the .productio-n of a source of signaling current of unitary structure, such as a generator,gwhich will cooperate with Asignaling devices in the manner previously mentioned.

The nature Vof the `invention and the method of applying the same will be more clearly seen by reference to theaccompanying drawings wherein t Figure 1 is a schematic representation of a telephone system embodying this invention; Fig. 2 is a diagrammatical representation of a source of current `or a generator suitable for ruse in the system of Fig. 1; Fig.

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i Application filed; December 2.9, ,19.1.6y Serial No. 139,553. i

3 represents the wave forinof `the `voltage generated by the generator; `and Fig. lfrepresents the wave form ofthe current flowing in the signaling devices during their'ac-` tuation. t i

Referring now to Fig. 1, the telephone system there` shown consistsof a pair of line conductors 5, 6, with one end of which are associated subscribers telephone` stations?, 8, 9 `and 10. IThe other end terminates in, a jaekata central station withwhichare associated the usual linerelay 11, line lamp manently `in series with the condenser 16 between one or the other of the line conductors and ground. 'lhe signaling-devices at stations 7 and 10 are connected between line conductor 5 and ground, while those at sta tions Sand 9 are connected between the other line conductor 6 and ground. Fach ,of these signaling devices is Voperable by current of only a single polarity, and hence they may be what are commonly known as biased ringers.`

For the purpose of this description it will bev assumed that the signaling devices or biased ringers at stations V7 and 8 are adapted to operate on current of positive polarity only, while those at stations 9l and 10will operate on current of negative polarity only. The

`reason for using Vbiased ringers and for connecting them into `the circuit as just de,- scribed is to obtain full selective ringing in a way hereinafter to be explained.

The cord circuit lll is of the well-known common battery repeating coil type, having a supervisory relay 17 and a four-button ringing key 18 adapted to connect signaling current of either positive or negative polarity to one or the other of the line wires depending upon which subscriberslstation is to be signaled. i

The source of signaling current, symbolically shown in Fig. 1 as 19 and 20, may consist of a generator, such as diagrammatically shown in Fig. 2. This generator has -tourfield poles 21, 22, 23 and 24, Ytwio of Vwhich' are'of one polarity and the other two .ofr'the opposite polarity, as shown by the symbols N, N and S, S. The two poles marked N, N are different in shape from those ymarked S, S. rIhe ring armature 25 rotates within the field poles andV is provided with four windings 26, 27, 28 and 29, each of which is concentrated on a small sector of the armature. 'Ihe two windings onopposite sectors,'such, for example, as 26 and `28, arejconnected inseries, and in such a way as to lald each other. The terminals of v one pair of kwindings are'connected to slip rings V30, 31, and those of the other pair to slip rings 30, 32, in such a way that slip ring Y 30vis commento both pairs, while slip rings l instant of time. .20

f this particular wave shape being due to the thewindings are passingunder these poles so .iiux distribution in the'several poles. Since the flux vin thevpoles marked S, S is substantiallyffequal to,` that in 'the larger poles markedN, N, itfollows'that the iux density is higher in the former, and, consequently, as

the maximum Y voltage generated will `be highery than that of opposite polaritygen- Verated. when the same windings arepassmg `under the kother pair of'poles. It is alsoV evident that the lengthot time occupied by 35.

a set of windings inpassing under the poles marked lS, ywill be less than that occupied Ywhile `the same windings are passingnn'der l the poles marked N, N. These conditions are represented by the voltagewave `of Fig. 3,v

where voltage of one polarity is generated for aperiod of time represented by c and of maximum value a, while voltage of opposite vpolarityand of maximum value Z), 1s genl erated for a length of .time represented byd.

.upon thelsystein of Fig.'1, produces a curySuch a voltaOe .wave vwhen im ressed rent inthe signaling devices', of 'substantially the-.wave formy shown inFig. 4; the form of the current ywave being determinedby the Vthe system. As there shown a current of one polarityv and of maximum value a flows relative values-of the electrical constants of for a period ottime represented by c", while f current of the opposite polarity, and of maximumY value'b, fiowsfor the length of time represented by df., `While the amount of energyrepresented by either part of this` current 'wave must necessarily be the same, the shape ofthe wave and the maximum value voit the current is quite different, and this dilference in the maximum value of the current is substantiallyv ameasure of the margin of selection in the signaling devices,`

i shown in Fig. 1.

The coperation between the signaling devices at the subscribers stations and the source of signaling current will be more clearly seen from a description ot thel operation ot the system, shown in Fig. 1.

Assume. that the operator at the central otice wishes to signal a party at subscriber-s station 7. .The cord circuit 14 will be connected to the subscribers line in the ordinary manner by means of the plug and jack, whereupon the cut-oit relay 13 will operate in a well-known manner to disconnect the line relay 11 from the line. The operator will then press the left-hand button of key 18, corresponding to station 7, which will impress signaling current from generator 19, whose maximum voltage is oi positive polarity, upon the line. The path of this current will be from the grounded side oI generator 19, left-hand upper alternate contact of key` 18line conductor 5, condensers 16 and signaling devices 15 of subscribers stations 7 'and 10 in parallel, to ground. Alternating current of wave form, shown in Fig. 3, will thereupon How through the sig naling devices 15, but only the device at subscribers station 7, will be actuated, the sig* naling device at'subscribers station 10 not responding because the maximum value ol the negative loop of the alternating current wave is not suiiciently high. I n a similar manner the signaling device at any ot the other stations may be actuated by operating the button of ringing key 18 at the central oflicecorresponding to that station.

A `wave form, substantially asV shown in Fig. 3, has been found to give the most satis factory results, and such a wave form can be obtained by the use of the generator hereinbefore described, coperating with a condenser 16 and a biased ringer 15. In the systems and with the sources of current heretofore available, it has been necessary to use a non-inductive resistance in shunt with the condenser in order to obtain approximately this same wave form of current. In those systems, however, the trouble, before noted, of decreased marginal Ioperation of the supervisory relays, was experienced. The introduction of such resistance furnished a leakage path-for battery, from the ring side of the line to ground, which path included the supervisory relay17. Such leakage path may be traced from the central oiiice battery through one winding of the repeating coil, supervisory relay 17, normal contacts of the ringing key 18, ring contacts of the plug and jack, line wire 6, non-inductive resistance (not shown), in shunt about the condenser and the biased'ringers 15 of stations 8 and 10 in parallel to ground. Thus, a current will How continuously through supervisory relay 17 as long as the cord circuit and line are connected Jfor conversation, through the plug and jack, and, therefore, will cnt down the margin of operation of the relay 17.

non-inductive resistance has not been used,

it has not beenpossible to obtain a `wave .form such as shown in Fig. 3, and therefore,` the margin of selection inthesignaling de vic'cs'has been comparatively low, 'and those systems `have consequently been impractical.

lin theforegoin.0' description the source of signaling current or the generator has beenrepresented as a four-pole machine having four windings, each concentrated uponfa comparatively small sector `of the armature. 1t is, of course, evident that two poles or any multiple thereof, could be used instead, providing the location of the windings were changed correspondingly.

Another variation within the scope of this invention is to increase the number of windings on the armature to completely utilize the available winding space, in which case each set of windings could be terminated on a pair of slip rings individual thereto or the sets could be terminated in pairs on three slip rings as shown in Fig. 2. By this arrangement a more eflicient and compact machine would result.

1t is further to be understood that other types of armatures and armature windings may be used in connection with this type of i'ield structure to produce substantially the same results as hereinbefore described, and their use will accordingly come within the scope of this invention, as defined by the accompanying claims.

What is claimed is: i

1. 1n a selective signaling system, line conductors, a plurality of biased signaling devices connected thereto, a signaling current generator comprising a plurality of magnetic poles of opposite polarities, a pole of one polarity being of different shape than a pole of the opposite polarity, and switching means for connecting said generator to one of said line conductors.

2. 1n a selective signaling system, line conductors, a plurality of biased signaling devices connected thereto, a signaling cur- I rent generator comprising a plurality of magnetic poles of opposite polarities, a pole of one polarity being of different shape than a pole of the opposite polarity, an armature for said generator having a concentrated winding, and switching means for connecting said generator to one of said conductors.

3. 1n a selective signaling system, line conductors, a plurality of biased signaling devices connected thereto, a condenser in series with each signaling device, a signaling current generator comprising a plurality of magnetic poles of opposite polarities, a pole of one polarity being of different shape than a pole of the opposite polarity, and

. switching means for connectingsaidgenerator to one of said line conductors. l 4t. 1n a selective signaling system, line conductors, aplnrality' of biased signaling devices connected` thereto., condenser in series with each `signaling device, a. signat ing current generator, an armature therefor having aconcentrated winding, and switch.-`

ing means-,for connecting said generator to one of said conductors. M

5; 1n a select ve signaling system, line conductors, a plurality of biased signaling devices connected thereto, a condenser in series with each signaling device, a signaling current generator comprising a plural` ity of magnetic poles of opposite polarities, a pole of one polarity being of different shape than a pole of the opposite polarity, an armature for said generator having a concentrated winding, and switching means for connecting said generator to one of said conductors.

6. 1n a selective signaling system, a line conductor, a plurality of biased signaling devices connected thereto, a signaling current generator comprising a plurality of magnetic poles of opposite polarities, a pole of one polarity being of different shape than a pole of the opposite polarity, an armature therefor having two similar concentrated windings oppositely wound with respect to the magnetic field between said poles, and switching means for connecting either of said windings to said line conductor.

7. 1n a selective signaling system, a line conductor, a plurality of biased signaling devices connected thereto, a condenser in series with Veach signaling device, a signaling current generator comprising a plurality of magnetic poles of opposite polarities, a pole of one polarity being of different shape than a pole of the lopposite polarity, an armature therefor having two similar concentrated windings oppositely wound with respect to the magnetic field between said poles, and switching means for connecting either of ,said windings to said line conductor.

8. 1n a selective signaling system, a twoconductor telephone line terminating at a central office, a plurality of subscribers" stations connected thereto, a biased signaling device individual to each subscribers station, two of said signaling devices being connected to each of said conductors and the two signaling devices which are connected to the same conductor being oppositely biased, a signaling current generator `comprising a plurality of magnetic poles of f fore'eonnecting either of saidiwindings to either of said-line conductors.

9.- In arselective signalingsystem, a twoconductor telephone line terminating at a central oiiice, a plurality of subscribers stations connected thereto, a biased signaling device individual to each subscribers station, two of saidfsignaling devices being connected to each of said conductors, the `two signaling devices which are connected gto the same conductor being oppositely biased, a condenser in series with each signaling device, a signaling current generator comprising a plurality of magnetic poles of opposite polarities, a pole of one polarity 15 eld between said poles, and switching' 20 means for connecting either of said Windings to either of said line conductors.

In witness whereof, I hereunto subscribe my name thie` 28th day of December A. D.,

STANLEY S. A. WATKINS.

" "-Copies'of this patent may be obtained for five cents each', by addressing the Commissioner of Patents,

Washington, D. G. 

